This invention relates to a holding device for glass panes, marble slabs and like bodies.
As is known, many industrial processes performed on glass panes and the like workpieces, require that the sheets or plates being processed be firmly held such as to create a desired opposing force to the thrust of tools at work on the sheet or plate. Another problem is that of conveniently handling the various plates or sheets, which may be heavy and of large size, in order to move them to the various places of utilization.
To hold a glass pane securely, suction cup elements of substantially conical shape are currently employed which are brought to contact the sheet to be held. The desired holding action, by firm adhesion of the suction cups to the sheet, is achieved by the suction cups being communicated to a vacuum source which draws out amounts of air present inside the area included between the suction cup and glass sheet.
Of course, the adhesion force generated is the greater the deeper is the vacuum that can be generated.
With this type of a device, the disadvantage is encountered, first of all, that a vacuum feeding circuit must be made available which is highly expensive, and the useful area of the suction cups must be fairly limited or otherwise the need would arise for a very powerful suction, with consequent waste of power.
Therefore, with suction cups of conventional design it is necessary to provide for a high number of suction cups in order to achieve an adequate sheet or plate holding force.